On automobiles, recreational vehicles, vans, small trucks, and virtually all other vehicles, a door check mechanism for each vehicle door is usually considered a necessity. In many applications, the door check mechanism provides two open positions, one at which the door is partially open and the other at which the door is fully open, though even the full open position is usually appreciably less than ninety degrees. In some applications the door check mechanism for a vehicle door provides only one open retention position.
Door check mechanisms of this sort are quite common and have been used for many years. However, they are far from uniform in construction or in application. In many vehicles the manufacturer provides a check mechanism that is separate from the door hinges. In this arrangement, particularly in small cars, each door is supported upon two simple hinges that do not establish any retained or detented open positions for the door. In other instances, particularly in larger automobiles, the manufacturer may prefer hinges that incorporate check mechanisms in the hinge structures. Thus, in a typical large car construction, each door is hung from two hinges, and one of those hinges includes a door check mechanism establishing two retention or detented positions for holding the door open.
Door check mechanisms, as applied to vehicle doors, have exhibited some substantial difficulties. Thus, the door check mechanisms used in automobiles and similar applications, whether separate from or combined with hinges, have frequently required lubrication, without which they tend to squeak and to make other undesirable noises. Some of these door check devices only produce noises when opened to full detented open position or beyond that position. Many of these door check mechanisms afford inadequate operating life; they do not last for the full life of the vehicle. In any of these door checks, corrosion may be a substantial problem. In at least some door check mechanisms, processing of the vehicle body after installation of the doors, particularly in the curing of external finishes, may require temperatures well beyond the tolerance range of materials used in the door check mechanisms. Thus, it is not uncommon for a vehicle body to be subjected, at least for a brief interval, to temperatures up to near 400.degree. F. after the door installations are completed. This may result in appreciable damage to a door check mechanism, whether incorporated in or separate from a door hinge, and may even require replacement of the door check.